1. Field of the Invention
This invention relates to stereophonic sound reproduction, and more particularly to a stereophonic sound system and method, and to a unique low frequency tranducer system for use therein.
2. Description of the Prior Art
As is well known, stereophonic type sound reproducing systems reproduce sound in such a manner as to convey a left to right distribution of the original sound source. Basically, in such systems, audio information obtained from a recording, tuner, or appropriate stereo source is processed into two separate channels and played through two separate loudspeaker systems spaced apart from each other at one end of a space, in such a manner as to reproduce left to right spatial distribution of the reproduced sound, primarily between the two separate loudspeakers, with the listener positioned at the other end of the space. The stereophonic systems in existence today produce excellent stereophonic effects at one end of a space, but fail to provide, in combination, sufficient sensations of depth, boundlessness, warmth and fullness normally associated with a concert hall situation, and insufficient, if any, sensation of height differentiation of sounds, without severe degradation of the intended stereophonic spatial image within the average living room listening environment. Stereophonic systems in existence today position the listener across a space from the reproduced performance and tend to exclude the listener from the space in which the reproduced performance is occuring, much like the way a standard motion picture projection system excludes the viewer from the space where the projected scene is taking place.
Basically, the present invention relates to a relatively simple way to place the listener in a more intimate relationship to the reproduced performance by creating an amphibinaural sound field, using auxiliary low frequency sound fields, ceiling and adjacent side wall reflections, and high definition directly radiated sound fields, that substantially surrounds the listener, an effect more like true binaural reproduction which includes the listener within the space of the occurring performance.
Examples of stereophonic sound reproducing systems which are in the patent literature, and which involves some manner of dividing out and separately amplifying low frequency sound are disclosed by U.S. Pat. No. 2,093,076, granted Sept. 14, 1937, to John F. Ingalls; by U.S. Pat. No. 2,179,840, granted Nov. 14, 1939, to Guestav Bucky; by U.S. Pat. No. 2,192,959, granted Mar. 12, 1940, to Randall C. Ballard; by U.S. Pat. No. 3,135,830, granted June 2, 1964, to Rudolph Starai; by U.S. Pat. No. 3,478,167, granted Nov. 11, 1969, to Morris Sorkin; and by U.S. Pat. No. 3,657,480, granted Apr. 18, 1972, to Theodore Cheng and James J. Hitt. The systems of these patents differ materially from the system of the present invention. However, the patents should be considered for the purpose of putting the invention into proper perspective relative to the prior art.
The subwoofer or sub-bass converter of the present invention reverses the direction of sound waves produced by a vibrating cone type speaker before releasing them. Examples of speakers in the patent literature which also involve a reversal in direction of sound waves are disclosed by U.S. Pat. No. 1,586,659, granted June 1, 1926, to John E. Davis, and by U.S. Pat. No. 2,390,834, granted Dec. 11, 1945, to Joseph Hegener.